The major objective of this study is to analyze the effects of psycho-active drugs on learning and memory in brain damaged animals. This approach will yield data concerning (1) pharmacological influences on learning and memory, (2) behavioral mechanisms of drug action, (3) behavior pathology resulting from brain damage and (4) compensatory processes involved in recovery of function following brain damage and the role of pharmacological agents in these processes. The interactions and dissociations resulting from the administration of representative drugs of several different types to multiple groups of animals with localized brain damage in several different regions should provide information regarding both neuroanatomical specificity of drug action and behavioral specificity of brain damage. The importance of environmental and situational factors will be evaluated by employing a wide range of behavioral testing techniques. The accumulation of diverse data will ultimately be integrated with the purpose of suggesting a therapeutic rationale for the administration of psychoactive drugs to functionally and organically disturbed humans.